In the cases of energy converting apparatuses (facilities) represented by combined heat and power (cogeneration) apparatuses that convert a fuel into at least kinetic energy, thermal energy, or electric energy, in order to measure the condition of such an apparatus, a technology of a Condition Based Maintenance (CBM) is known which installs a plurality of sensors (measuring instruments), measures and grasps the condition of the apparatus from time to time through those sensors, determines the normal or abnormal condition of the apparatus based on the measured data (referred to as apparatus condition measured data or sensor data, etc.), and carries out a maintenance in view of the abnormal condition.
In order to carry out the condition based maintenance (CBM) effectively, it is necessary to find a sign of an abnormality before the apparatus breaks down. An effective method to find a sign of an abnormality is to statistically analyze pieces of data of the plurality of condition measuring sensors, to obtain reference data from the condition measuring sensor when an apparatus is in a normal condition, and to check data measured from time to time with the reference.
In the cases of energy converting apparatuses, most modules constructing the apparatus and components constructing the module are operated in association with each other to let the apparatus to accomplish the object like energy conversion. Hence, most outputs by the plurality of sensors installed for the plurality of components, etc., constructing the apparatus change in association with each other. Accordingly, if the relationship among respective sensor outputs that change in association with each other in the normal condition is compared with the relationship among respective sensor outputs that change in association with each other in the abnormal condition to create a model, it becomes possible to diagnose a cause of an abnormality (a defect) after the abnormal condition has been detected.
For example, Patent Literatures 1 and 2 disclose a method of analyzing a causal association between a product quality in a production line and process data through a graphical model, which is not an example of the condition based maintenance (CBM) of an apparatus, though. Moreover, Non-patent Literature 1 discloses a typical statistical and mathematical algorithm method of analyzing a causal association through a graphical model.